The investigators propose to build CCD area detectors for X-ray diffraction studies at synchrotron radiation sources, using a new, large-format (62mm x 62mm, 4,096 pixels) CCD now being manufactured by Lockheed Martin Fairchild Systems to build three progressively more advanced instruments, as further described by their abstract: "The overall objective of this project is to develop high-performance, high resolution, programmable-readout detectors optimized for biological x-ray diffraction application. The detector design is based on a new generation of very large format Charge Couple Devises (CCDs). This new instrumentation will allow researchers at synchrotron beam lines to take full advantage of these x-ray sources to perform demanding experiments either not practical, or not possible, with current detectors. Furthermore, the new detectors will have higher performance and lower cost relative to existing instruments for conventional x-ray protein crystallography on both synchrotron and laboratory sources. "Today's CCD-based detectors for x-ray diffraction optically couple a phosphor x-ray converter to a relatively small CCD with a demagnifying fiberoptic taper. The demagnifying tapers, which are required because of the small size of previously-available CCDs, reduce sensitivity, degrade spatial resolution, and introduce background events due to radioactive contaminants in the glass. Furthermore, they are physically large and expensive. CCD sensors with areas of -60x60mm have recently become available at a relatively low cost. These CCDs allow the design of large-area x-ray detectors composed only of an x-ray-to- light converter optically coupled, without demagnifying tapers, to an array of CCDs. Compared to current crystallography detectors, the new detectors will have a higher efficiency for measuring low- intensity signals, higher spatial resolution, and a larger dynamic range. This higher-efficiency optical design will allow the detector to be efficiently used for demanding x-ray diffraction applications such as virus crystallography, small-angle scattering. Multiwavelenth Anomalous Diffraction, Laue diffraction, measurement of diffuse scatter, and high-resolution imaging. A programmable controller will allow collection of data from time- resolved experiments such as muscle diffraction. "The goal of the project will be accomplished by (a) the development of methods required for utilizing the new large-format CCDs, (b) the construction and evaluation of a prototype 1-CCD detector, " the construction and evaluation of a 2-CCD detector, and (d) the construction and evaluation of a 9-CCD detector. The 2-CCD detector will be permanently installed at the BioCAT beamline at the Advanced Photon Source where it will be used primarily for small- angle scattering from biological materials. The 9-CCD detector will be permanently installed at the National Synchrotron Light Source and used primarily for macromolecular crystallography. The addition of these detectors to APS and NSLS beamlines will significantly increase the utility of both of these national resources."